Currently used lubrication systems include a bushing disposed within a housing. The lubrication system may be configured to direct a lubricant, such as grease, to an inner surface of the bushing. In a current design, a hole needs to be drilled through the housing in order to carry the grease to the center of the bushing. This drilling operation adds time and cost to the manufacturing process. Some of the current designs also include angled or helical grooves on an inner surface of the bushing. These grooves allow distribution of the grease over the surface of a bearing disposed within the bushing.
For example, U.S. Pat. No. 2,625,448 describes a bearing lubrication system wherein a bushing has spaced slots along the length of the bushing on its outer face and holes connecting the opposite ends of the slots with circumferentially formed oil grooves.